Trenton is a city in and the county seat of Gilchrist County, Florida, United States. The population was 2,015 as of the 2020 census, up from 1,9…Trenton is a city in and the county seat of Gilchrist County, Florida, United States. The population was 2,015 as of the 2020 census, up from 1,999 at the 2010 census. It is part of the Gainesville, Florida Metropolitan Statistical Area.